ANTONIEA POIATĂ*, CRISTINA TUCHILUS*, DORINA CREANGĂ**, CRISTINA STAN***

*Faculty of Medicine, ”Grigore T. Popa” University, Iași, Romania
**Faculty of Physics, ”Alexandru Ioan Cuza” University, Iași, Romania
***University ”Politehnica” București, Romania

Two suspensions of magnetic nanoparticles were prepared based on chemical coprecipitation of magnetite (MN1) and cobalt ferrite (MN2) from iron and respectively iron and cobalt salts, the magnetic powders being coated in sodium oleate for stabilization in deionized water. Microstructural and magnetic characterization was accomplished in both cases by applying standard methods. Two bacterial strains: Staphylococcus aureus – a Gram positive germ, and Escherichia coli – a Gram negative microorganism were cultivated in nutrient broth by adding 0.1 μL/mL magnetic nanoparticle suspension. Cell density was assessed by means of optical density measurements and calibration curve evidencing the inhibitory effect of magnetic nanoparticles on the bacterial cell growth. The diminution of S. aureus cell density was the most remarkable – more than 50% decrease compared to the control level for MN1 and MN2 test variants. E. coli response was consistent with smaller negative variations of the cell density following the treatment with magnetic nanoparticles – the cell density decreasing up to 93% for MN1 and MN2 samples.

Corresponding author’s e-mail: dorina.creanga@gmail.com

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